Resolves: tdf#145853 Add Interslavic Latin|Cyrillic to language list

Interslavic Latin {art-x-interslv} 0x06AD
Interslavic Cyrillic {art-Cyrl-x-interslv} 0x06AE

Change-Id: I487d6593db89af038555a192674298e2dabf5582
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/127018
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins
(cherry picked from commit 430a6fea4012752eed0c61bff4936e9c366aa750)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/126981

3 files changed, 7 insertions, 1 deletions

diff --git a/i18nlangtag/source/isolang/isolang.cxx b/i18nlangtag/source/isolang/isolang.cxx
index 36b69f0fe6a6..b29726342733 100644
--- a/i18nlangtag/source/isolang/isolang.cxx
+++ b/i18nlangtag/source/isolang/isolang.cxx
@@ -781,6 +781,8 @@ Bcp47CountryEntry const aImplBcp47CountryEntries[] =
 //  { LANGUAGE_YUE_CHINESE_HONGKONG,         "zh-yue-HK", "HK", "", 0 },   // MS reserved, prefer yue-HK; do not add unless LanguageTag::simpleExtract() can handle it to not call liblangtag for rsc!
     { LANGUAGE_YIDDISH,                          "yi-001",   "", "", k0 },  // MS since rev.15, was "yi-Hebr" reserved, "001"="World"
     { LANGUAGE_FRENCH_WEST_INDIES,               "fr-029",   "", "", k0 },  // MS since rev.15, was "Neither defined nor reserved", "029"="Caribbean"
+    { LANGUAGE_USER_INTERSLAVIC_LATIN,     "art-x-interslv", "", "", k0 },  // see discussion in tdf#145853
+    { LANGUAGE_USER_INTERSLAVIC_CYRILLIC, "art-Cyrl-x-interslv", "", "", k0 },
     { LANGUAGE_DONTKNOW,                    "", "", "", k0 }    // marks end of table
 };
 
diff --git a/include/i18nlangtag/lang.h b/include/i18nlangtag/lang.h
index ae434fd0c06a..39f9abf8de56 100644
--- a/include/i18nlangtag/lang.h
+++ b/include/i18nlangtag/lang.h